Due to a rapid development of economic construction, a large number of major foundation projects such as water conservancy and hydropower projects, and railway and highway traffic projects, have accelerated the pace of construction, the focus of construction has shifted to the mountainous and karst areas in the western regions where the terrain and geological conditions are extremely complicated. This greatly promotes the construction of tunnel projects. In order to improve the stability of surrounding rocks and the construction safety during tunnel construction with karst caves, weak surrounding rocks usually require arch support installation. After the initial support of the construction of karst tunnels, and before the construction of the second lining, collapse of the tunnels often cause irreparable damage to the arch frame, resulting in serious casualties, delays of construction periods, and economic losses. Experts and scholars have not yet developed an effective arch protection measure or device for the rockfall and collapse disasters of tunnels containing karst caves. Therefore, it is necessary to invent an arch flexible protection device and early warning system for rockfall and collapse of tunnels containing karst caves and in underground constructions so that construction units can grasp the information of collapse accurately in time and take emergency measures as soon as possible to reduce losses.